In a conventional rotor for a vehicular AC power generator, a slip ring device is attached to a shaft in order to feed power to a field coil. The slip ring device is formed by integrally molding a pair of slip rings and connection terminals for electrically connecting the field coil to the slip rings in a mold. The shaft is supported in a housing via a pair of bearings. The slip ring device is attached to one of the bearings, and two shaft grooves extending along an axis of the shaft are provided in a part of the shaft to which this bearing is fitted. Beam portions in which the connection terminals are covered by the mold are accommodated respectively in the shaft grooves. The connection terminals pass through the beam portions accommodated in the shaft grooves from the slip rings and extend beyond the bearing so as to reach a side of the bearing opposing the field coil (see PTL 1).
In another conventional rotor for a vehicular AC power generator, improvements are achieved in the electric insulation performance and mechanical strength of a field coil wound around a resin bobbin by impregnating the field coil with thermosetting resin (see PTL 2).
In a further conventional rotor for a vehicular AC power generator, processing for fixing a fusing connection portion reliably, the fusing connection portion being a connecting portion connecting a lead wire of an excitation coil to a connection bar extending from a slip ring, is performed by forming a barrier portion that surrounds the periphery of the fusing connection portion on a part of a cooling fan provided on a side portion of a pole core of the rotor, and providing an insulation treatment agent for fixing the fusing connection portion in the barrier portion (see PTL 3).